The present invention is concerned with a spray device for irrigation, and is particularly concerned with an irrigation spray stake device for irrigating landscape and/or nursery plants.
Existing irrigation spray stake devices typically have a vertical stake for embedding in the soil adjacent a plant to be irrigated, and a vertical peg projecting upwardly from the stake over which a small diameter, flexible plastic water supply tube is fitted. The peg has a vertical groove and a horizontally oriented deflector plate at the bottom of the groove. The tube covers most of the peg, but leaves a small portion of the groove uncovered at the bottom to allow water to exit. The pressurized water is deflected off the horizontal deflector plate into a fine spray. The deflector plate is typically flat and the supply groove is generally V-shaped. A spray device of this type is described, for example, in U.S. Pat. No. 3,638,863 of Roberts.
Spray stakes are manufactured in a precision injection molding process, which results in consistent and accurate parts. However, the water supply tubing used with the spray stakes may have larger manufacturing variations. Also, the end of the tubing is usually cut in the field by growers using scissors or wire cutters, and may not be cut straight across. As a result, the flow rate, spray pattern shape, and overall performance of the spray stake device will vary dependent on the properties and configuration of the water supply tube and cut end thereof. The V-shaped water supply grooves employed by existing spray stakes make contact with the tubing at the widest point in the groove, further increasing the dependency of performance on tubing properties.
V-shaped supply grooves also tend to deflect a large amount of water in a direction parallel to the angled walls of the V, causing the resultant spray pattern to have higher flow rates along the edges and lower flow rates in the center of the pattern. This will result in uneven watering, and is not desirable.
The deflector plate at the lower end of the supply groove of existing spray stake devices is typically flat and horizontal. In some devices, the plate is angled downward, but still flat, or may have a step which results in portions of the plate being at different angles. These existing deflector plates produce spray patterns which are not optimized for irrigating plants in nursery containers. Flat, horizontal deflector plates result in broad spray patterns which are larger than any practical container. The water then sprays into the edges of the containers and drips onto the soil in the edge, instead of uniformly covering the root zone of the plant. Also, the large amount of water along the edges of the container causes the soil to separate from the container and allows water to pass directly out of the container without going through the soil.
A downwardly sloping flat deflector plate with a small horizontal step at the bottom of the plate in the center of the spray pattern has also been used in past spray stakes. This directs the spray more uniformly throughout the container. Water on the edges of the spray pattern moves in a downwardly directed path, due to the downwardly sloping edges of the deflector plate, while water in the center of the spray pattern moves in a direction with less of a downward slope due to the horizontal step. The result is a cone shaped spray pattern which is desirable with nursery container plants. However, the step configuration tends to cause the spray pattern to be heavier at the side edges of the step, resulting in two heavy side streams and lighter coverage throughout the remainder of the container, which is undesirable.
It is an object of the present invention to provide a new and improved spray device for irrigation.
According to one aspect of the present invention, a spray device is provided which comprises, a substantially cylindrical peg for insertion into a water supply tube, a longitudinal water supply groove extending along the peg, the groove having opposite ends, and a water deflecting plate at one end of the groove for deflecting water traveling along the groove into an outwardly directed spray, the groove being of U-shaped cross-section and having a longitudinal opening directed radially outwardly from the peg. The peg may be mounted on a support body such as an elongated ground penetrating stem for supporting the peg upright adjacent a region to be watered.
The U-shaped groove will make contact with the supply tubing over a smaller area than a V-shaped groove for the same cross-sectional area, since the U-groove will be narrower at its outer extremity. Since flow rate is proportional to cross-sectional area, the performance of the spray device with a U-shaped groove will be more consistent and less dependent on the properties of the supply tubing and how the end is cut. The U-shaped groove will also have reduced tendency to divert water to the edges of the spray pattern, resulting in a more uniform spray and more consistent irrigation.
According to another aspect of the present invention, a spray device is provided which comprises, a substantially cylindrical peg for insertion into a water supply tube, a longitudinal water supply groove extending along the peg, the groove having opposite ends, and a water deflecting plate at one end of the groove for deflecting water traveling downwardly along the groove into an outwardly directed spray, the water deflecting plate having a smooth, convex curved shape.
In one exemplary embodiment, the water deflecting plate has a steeper downward slope at its outer edges than at the center of the plate. The plate may be of part conical shape, forming part of a cone which may be inclined at a non-perpendicular angle to the axis of the stake and peg. In one example, the conical shape forms part of a cone with the downward slope of the center of the plate inclined at an angle in the range from 20xc2x0 to 50xc2x0 to the horizontal direction. Due to the conical shape and tilt of the cone, the central portion of the deflecting plate will be at a more shallow angle than the outer edges of the plate, and the slope of the plate will move smoothly and progressively from the steep angle at the edges to the shallow angle at the center.
The water deflecting plate is designed to produce a smooth, continuous cone-shaped spray which is desirable for irrigation of nursery container plants. The absence of sharp steps eliminates the formation of heavy water streams within the spray pattern, and water splashing into the edges of the container will be minimized if the proper flow rate sprayer is selected.
The deflecting plate may have a flat, inclined portion or land extending around all or part of the bottom edge of the plate, in order to break up the spray and further direct it. The supply groove may be of V-shaped or U-shaped cross-section.
The conical shape deflecting plate in the spray device of this invention produces a more uniform and conical shaped spray which is desirable for watering plants in nursery containers. The shape of the plate is such that heavy water stream formation in the spray is substantially eliminated, and the spray can readily be arranged so that water will not splash into the container edges, reducing the risk of soil separation and water running out of the container without passing through the soil. The U-shaped supply channel, whether used alone or in conjunction with the shaped deflecting plate, provides greater flow control, and more consistent irrigation uniformity.